In Morocco, it is generally considered that post‐Hercynian vertical movements were limited to the Atlas system, the passive continental margin and the Rif. Apatite FT and He ages from the Moroccan Meseta (Rehamna and Zaer Massif) document instead two episodes of subsidence and exhumation in Jurassic‐Early Cretaceous and during the Late Cretaceous to Neogene. The Meseta subsided to >3 km depth during the Late Triassic to Middle Jurassic and was exhumed to the surface before the Late Cretaceous, during the rift and post‐rift stages of Central Atlantic opening. Erosion of the exhuming rocks is responsible for a thick package of terrigenous sands found in the Moroccan offshore and elsewhere along the NW Africa margin. About 1 km of subsidence affected the Meseta during the Late Cretaceous to Eocene. During the Neogene, these areas were brought back to the surface in association with bimodal folding with wavelengths of 100–150 km and >500 km.

To put constraints on the Mesozoic to recent growth of the Anti-Atlas system, we investigated the temperature-time history of rocks by applying extensive low-temperature thermochronological analysis to three Precambrian inliers along the coast and 250 km into the interior. Bedrocks yield old U-Th ⁄ He ages on zircon and apatite (150-50 Ma) and also fission-track ages of 173-121 Ma on apatite. These datasets are interpreted as recording passive margin upward movements from central Atlantic rifting until the Early Cretaceous. A phase of sedimentary burial was evidenced for the Cretaceous-Eocene. The extension of this thin (1.5 km) basin is loosely constrained but can be extended to the western regions of northern Africa. Effects of the existing thermal perturbation of lithospheric origin 100 km below the Atlas show that the 120-60°C isotherms are not much deflected. Large-scale uplift has possibly occurred in the western Anti-Atlas since c. 30 Ma and is associated with a mean denudation rate of 0.08 km Ma )1 .

International audienceThe Ladakh Batholith is part of the Transhimalayan Plutonic Belt, which crops out north of the Indus Suture Zone. We propose that the exhumation history of the Ladakh Batholith is linked to the tectonic, magmatic and erosion history of the Karakoram terrane and SW Tibet. We present new multiple low-temperature thermochronometry data (zircon (U–Th)/He, apatite fission-track and apatite (U–Th)/He) to gain insight into the cooling history of the Ladakh Batholith and recognize key periods in the evolution of the region. From the Indus Valley northwards the ages decrease across the batholith for all three thermochronometers applied. A model is proposed in which magmatism in the Ladakh Batholith ceased in the Late Eocene and initial denudation was driven by topographic uplift caused by collision. Southward tilting of the batholith occurred in the Late Palaeogene. This tilting resulted in an asymmetric topography with increasing elevation to the north. Strong erosion occurred in this northern region whereas the southern margin was affected by northwards thrusting of the Indus Molasse. For the first time, clear temporal and spatial variations in exhumation rate are identified in this region, highlighting why sampling strategy is critical in documenting exhumation changes in active tectonic settings

[1] Apatite fission track (AFT) and (U-Th)/He (AHe) thermochronology have been combined to constrain the exhumation history of the SE Carpathians. Cooling ages generally decrease from Cretaceous for the internal basement nappes (AFT ages), to Miocene-Quaternary (AFT and AHe, respectively) for the external sedimentary wedge. The AFT and AHe data show a Paleogene age cluster, which confirms a suspected but never demonstrated tectonic event. The new data furthermore suggest that the SE Carpathians have been affected by a middle Miocene exhumation phase related to continental collision, which occurred at rates of ∼0.8 mm/yr, similar to the one previously inferred for the East Carpathians. The SE Carpathian tectonic evolution, however, is overprinted by two younger exhumation events in the Pliocene-Pleistocene. The first exhumation phase (latest Miocene-early Pliocene) occurred at high exhumation rates (∼1.7 mm/yr) and is interpreted as a tectonic event and/or associated with a sea level drop in the Paratethys basins during the Messinian low stand. The youngest recorded tectonic phase suggests rapid Pleistocene exhumation (∼1.6 mm/yr) and is interpreted to represent crustal-scale shortening different in mechanics from collisional processes. The data suggest that the SE Carpathians did not develop as a typical double-vergent orogenic wedge; instead, exhumation was related to a foreland-vergent sequence of nappe stacking during collision and was subsequently followed by a large out-of-sequence shortening event truncating the already locked collisional boundary.

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